Ball Mill grinds material by rotating a cylinder with steel grinding balls, causing the balls to fall back into the cylinder and onto the material to be ground. The rotation is usually between 4 to 20 revolutions per minute, depending upon the diameter of the mill. The larger the diameter, the slower the rotation. Ball mill are generally used to grind material 1/4 inch and finer, down to the particle size of 20 to 75 microns. To achieve a reasonable efficiency with ball mills, they must be operated in a closed system. Various classifiers, such as screens, spiral classifiers, cyclones and air classifiers are used for classifying the discharge from ball mills. Ball mill is an efficient tool for grinding many materials into fine powder, is widely used in building material, chemical industry, etc. There are two ways of grinding: The dry process and the wet process. It can be divided into tabular type and flowing type according to different forms of discharging material. The ball mill is a horizontal rotating device transmitted by the outer gear. The materials are transferred to the grinding chamber through the quill shaft uniformly. There are ladder liner, ripple liner and different specifications of steel balls in the chamber. The centrifugal force caused by rotation of barrel brings the steel balls to a certain height and impact and grind the materials. The ground materials are discharged through the discharging board thus the grinding process is finished.